Muscles bring about movement at a [blank_start]joint[blank_end]; most movements are produced by the co-ordinated action of [blank_start]several[blank_end] muscles. Muscles [blank_start]shorten[blank_end], pulling on the bone and so moving the joint. Muscles can only [blank_start]pull[blank_end], they can't [blank_start]push[blank_end], so at least [blank_start]two[blank_end] muscles are needed to move a bone to and fro. A pair of muscles that work in this way are described as [blank_start]antagonistic[blank_end]. A muscle that contracts to cause [blank_start]extension[blank_end] of a joint is called an [blank_start]extensor[blank_end]; the corresponding [blank_start]flexor[blank_end] muscle contracts to reverse the movement.
Answer
joint
several
shorten
pull
push
two
antagonistic
extensor
flexor
extension
Question 2
Question
Which of the following are examples of synovial joints?
Answer
hip
knee
ankle
synapse
Question 3
Question
[blank_start]Synovial[blank_end] joints; the bones that articulate (move) in the joint are separated by a cavity filled with [blank_start]synovial fluid[blank_end], which enables them to move freely. They all have the same basic structure.